Air conditioner

Abstract

An air conditioner has a refrigerant circuit filled with a predetermined amount of a refrigerant, the circuit being formed of an outdoor unit and an indoor unit connected to each other by refrigerant piping, the outdoor unit having a compressor, an outdoor heat exchanger, and an expansion valve, the indoor unit having an indoor heat exchanger. The conditioner has an estimation model that estimates an amount of remaining refrigerant remaining in the circuit by using at least rotation frequency of the compressor, refrigerant discharge temperature at the compressor, heat exchanger temperature, degree of opening of the expansion valve, and outside air temperature, of operation state quantities indicating operation states during operation. The indoor heat exchanger has a sensor that is provided at an indoor heat exchanger intermediate portion connecting a first indoor heat exchanger port and a second indoor heat exchanger port to each other.

The invention claimed is: 
     
       1. An air conditioner having a refrigerant circuit formed by connection of an outdoor unit and an indoor unit to each other by refrigerant piping, the outdoor unit having a compressor, an outdoor heat exchanger, and an expansion valve, the indoor unit having an indoor heat exchanger, the refrigerant circuit being filled with a predetermined amount of a refrigerant, the air conditioner comprising:
 a remaining refrigerant amount estimation model that estimates an amount of remaining refrigerant remaining in the refrigerant circuit by using at least rotation frequency of the compressor, refrigerant discharge temperature at the compressor, heat exchanger temperature, degree of opening of the expansion valve, and outside air temperature, of operation state quantities indicating operation states in air conditioning operation, wherein the estimate of the amount of remaining refrigerant is performed during both a heating operation and a cooling operation of the air conditioning operation, wherein 
 the indoor heat exchanger includes:
 a first indoor heat exchanger port portion where the refrigerant flows through; a second indoor heat exchanger port portion where the refrigerant flows through; an indoor heat exchanger intermediate portion connecting the first indoor heat exchanger port portion and the second indoor heat exchanger port portion to each other; and an indoor heat exchanger intermediate sensor that is provided at the indoor heat exchanger intermediate portion and detects temperature of the refrigerant passing through the indoor heat exchanger intermediate portion, the temperature being of the heat exchanger temperature, and 
 
 the outdoor heat exchanger includes:
 a first outdoor heat exchanger port portion where the refrigerant flow through; a second outdoor heat exchanger port portion where the refrigerant flows through; an outdoor heat exchanger intermediate portion connecting the first outdoor heat exchanger port portion and the second outdoor heat exchanger port portion to each other; and an outdoor heat exchanger outlet port sensor that is provided at the second outdoor heat exchanger port portion and detects temperature of the refrigerant passing through an outdoor heat exchanger outlet port in the second outdoor heat exchanger port portion in cooling operation, the temperature being of the heat exchanger temperature. 
 
 
     
     
       2. The air conditioner according to  claim 1 , wherein there is only one of the outdoor unit,
 wherein there is only one of the indoor unit, and 
 wherein there is only one of the expansion valve. 
 
     
     
       3. The air conditioner according to  claim 1 , wherein the remaining refrigerant amount estimation model estimates the amount of remaining refrigerant by using an operation state quantity obtained at a time an absolute value of a difference between the refrigerant discharge temperature at the compressor and a target temperature is equal to or less than a predetermined value. 
     
     
       4. The air conditioner according to  claim 1 , wherein the remaining refrigerant amount estimation model performs machine learning using training data that are the rotation frequency of the compressor, the refrigerant discharge temperature at the compressor, the heat exchanger temperature, the degree of opening of the expansion valve, the outside air temperature, and the amount of remaining refrigerant remaining in the refrigerant circuit. 
     
     
       5. The air conditioner according to  claim 4 , wherein the remaining refrigerant amount estimation model is a linear regression equation. 
     
     
       6. The air conditioner according to  claim 1 , wherein the remaining refrigerant amount estimation model performs machine learning using training data that are results of determination of whether or not the rotation frequency of the compressor, the refrigerant discharge temperature at the compressor, the heat exchanger temperature, the degree of opening of the expansion valve, the outside air temperature, and the amount of remaining refrigerant remaining in the refrigerant circuit are normal. 
     
     
       7. The air conditioner according to  claim 1 , wherein the estimate of the amount of remaining refrigerant is performed absent a refrigerant filling operation. 
     
     
       8. The air conditioner according to  claim 1 , wherein the remaining refrigerant amount estimation model estimates the amount of remaining refrigerant remaining in the refrigerant circuit without calculating a degree of supercooling and by using at least a rotation frequency of the compressor, a refrigerant discharge temperature at the compressor, a heat exchanger temperature, a degree of opening of the expansion valve, and an outside air temperature, of operation state quantities indicating operation states in a normal operation of the air conditioner. 
     
     
       9. The air conditioner according to  claim 8 , further including a plurality of sensors for detecting each of the rotation frequency of the compressor, the refrigerant discharge temperature at the compressor, the heat exchanger temperature, the degree of opening of the expansion valve, and the outside air temperature, of the operation state quantities indicating the operation states in the normal operation of the air conditioner,
 wherein the plurality of sensors includes:
 the indoor heat exchanger intermediate sensor that detects the temperature of the refrigerant passing through the indoor heat exchanger intermediate portion, and 
 the outdoor heat exchanger outlet port sensor that detects, when the outdoor heat exchanger functions as a condenser, the temperature of the refrigerant passing through an outlet port of the condenser, and 
 the air conditioner includes an extractor that extracts, according to a predetermined filtering condition, a detection result used in estimating the amount of remaining refrigerant from a result of the detecting by the plurality of sensors.